Chapter 18- Interstellar Medium

Front 1

Interstellar Medium

Back 1

Made up of two components: gas and dust, which is intermixed throughout all space.
Sometimes bright and colorful, sometimes dark due to dust blocking the background starlight.

Front 2

Regions of space where (blank), blocks the light from stars beyond. Composed of hydrogen and helium.

Back 2

Interstellar Medium

Front 3

consisting of clumps of atoms and molecules in the interstellar medium

Back 3

Interstellar Dust

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Dust Grains

Back 4

typical interstellar dust particle

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True or False: dusty regions of interstellar space are transparent to long wavelength radio and infrared radiation.

Back 5

True

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Extinction

Back 6

overall dimming of starlight by interstellar medium

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True or False: Interstellar medium is more opaque to short-wavelengths radiation than to radiation of longer wavelengths, often causing what?

Back 7

True: results in light from distant stars to being robbed of its higher frequency, blue. This leads to the reddening effect.

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an effect where stars tend to appear redder than what they really are

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Reddening

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What makes interstellar space a relatively dirty place?

Back 9

Dust Particles

Front 10

using a beam of light can absorb or scatter only the particles that have a diameter comparable to or larger than the wavelength of radiation involved

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Using the effects of starlight to measure amount and size of interstellar dust.

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Is the density of the interstellar medium high or low?

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Extremely Low.

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Composition of interstellar gas

Back 12

Silicates, graphite and iron

Front 13

Composition of interstellar dust

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90% of the gas is a atomic or molecular hydrogen.

9% is helium

1% consists of heavier elements. Abundances of heavy elements include carbon, oxygen, silicon, magnesium and iron.

Front 14

What evidence best supports that interstellar dust forms out of interstellar gas?

Back 14

Composition of interstellar gas which shows elements are under-abundant in the gas

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Dirty Ice

Back 15

frozen mixture of ordinary water contaminated with ammonia, methane, and other chemical compounds. Dirty ice is usually found in the interstellar dust.

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Starlight provides a mean of studying particles based on the fact that light emitted by stars is dimmed partially (answer)

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Polarization

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Nebula

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term that refers to any fuzzy patch (bright or dark) on the sky. Any region of space that was clearly distinguishable. Many (blank) are clouds of interstellar dust and gas.

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Emission Nebulae

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glowing clouds of hot interstellar matter.

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Dust Lanes

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Often crossed by Nebulae, part of the larger cloud which they formed.

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Caused by starlight scatted from dust particles in interstellar clouds, they appear blue for much the same blue light more easily scattered by interstellar matter.

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Reflection Nebula

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Dark Dust Clouds

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Dark Molecular Clouds

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Molecular Cloud Complex